The present invention relates to an aerodynamically shaped, aircraft mounted static pressure sensing probe that extends a short distance outwardly beyond the boundary layer on the surface of the aircraft, and provides reliable static pressure measurements, with a low drag configuration.
Various static pressure sensing probes have been advanced in the prior art, some of which include configurations that modify the static pressure sensed at locations along the probe. U.S. Pat. No. 4,730,487 shows a strut mounted probe, that has static pressure sensing ports on the surface, with pressure modifying surface irregularities provided. A strut mounted dual static tube or probe is shown in U.S. Pat. No. 3,482,445.
The strut mounted probes as shown in the prior art add drag, and weight, and while reliable, the desirability of having small, lightweight, low drag probes that will withstand reasonable impacts exists. The probes also need to provide reliable static pressure sensing with accuracy needed to meet present reduced vertical separation minimum (RVSM) requirements of air traffic control.
Static pressure sensing ports in flush plates, that form continuations of the aircraft surface, are affected by the skin waviness of an aircraft, as well as the boundary layer of air on the skin. The strut mounted pitot static probes that are used do extend outside the boundary layer, but the strut mounted probes also require substantial amounts of power for heating to prevent icing. Since a strut is used, there is relatively high drag and weight. The increasing demands on accuracy in maintaining vertical separation for the flight levels for civil aircraft under positive control of the air traffic control system have required greater accuracy in sensing static pressure, and flush sensor plates with static ports generally do not meet these accuracy requirements.